Influence of Mo Doping on the Microstructure, Friction, and Wear Properties of CrAlN Films

In this study, closed-field unbalanced magnetron sputtering ion-plating technology is used to deposit CrAlMoN and CrAlN nanomultilayer films on the surfaces of M2 tool steel and single-crystal Si. Energy-dispersive spectroscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, x-ray diffraction, scratch tester, nanoindenter, and pin-on-disk wear tester are used to study the influence of Mo doping on the composition, microstructure, mechanical properties, and friction properties of CrAlN films. Results show that CrAlMoN films have a nanomultilayer structure, CrN/Mo2N/CrN/AlN, with a modulation period of 10.5 nm. After Mo doping, the face-centered cubic structure of CrAlMoN films remains the same as that of CrAlN films. The chemical valence of each element in CrAlN films does not change with Mo doping. At room temperature, the wear resistance of CrAlMoN films is significantly improved compared with that of CrAlN films. This is attributed to the significant antifriction effect of MoO3 that forms on CrAlMoN films doped with Mo during the friction process.